21131263651020 has 48 divisors (see below), whose sum is σ = 59168468738400. Its totient is φ = 5634915019776.

The previous prime is 21131263650961. The next prime is 21131263651021. The reversal of 21131263651020 is 2015636213112.

It is not an unprimeable number, because it can be changed into a prime (21131263651021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1122756 + ... + 6597204.

It is an arithmetic number, because the mean of its divisors is an integer number (1232676432050).

Almost surely, 2^{21131263651020} is an apocalyptic number.

21131263651020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21131263651020 is an abundant number, since it is smaller than the sum of its proper divisors (38037205087380).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21131263651020 is a wasteful number, since it uses less digits than its factorization.

21131263651020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5538794 (or 5538792 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 33.

Adding to 21131263651020 its reverse (2015636213112), we get a palindrome (23146899864132).

The spelling of 21131263651020 in words is "twenty-one trillion, one hundred thirty-one billion, two hundred sixty-three million, six hundred fifty-one thousand, twenty".